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netinet6: honor blackhole/unreach routes in the non-fastforwading code.

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Currently, under the conditions specified below, IPv6 ingress packet
 processing can ignore blackhole/reject flag on the prefix. The packet
 will instead be looped locally till TTL expiration and a single ICMPv6
 unreachable message will be send to the source even in case of
 RTF_BLACKHOLE.
The following conditions needs hold to make the scenario happen:
* IPv6 forwarding is enabled
* Packet is not fast-forwarded
* Destination prefix has either RTF_BLACKHOLE or RTF_REJECT flag
Fix this behavior by checking for the blackhole/reject flags in
ip6_forward().

Reported by:	Dmitriy Smirnov <fox@sage.su>
Reviewed by:	ae
Differential Revision: https://reviews.freebsd.org/D38164
MFC after:	3 days
This commit is contained in:
Alexander V. Chernikov 2023-01-22 16:57:36 +00:00
parent 7a56009cf5
commit 30dd227cff
1 changed files with 9 additions and 0 deletions
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9
sys/netinet6/ip6_forward.c
View File

@ -196,6 +196,15 @@ ip6_forward(struct mbuf *m, int srcrt)
goto bad;
}
if (nh->nh_flags & (NHF_BLACKHOLE | NHF_REJECT)) {
IP6STAT_INC(ip6s_cantforward);
if ((nh->nh_flags & NHF_REJECT) && (mcopy != NULL)) {
icmp6_error(mcopy, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_REJECT, 0);
}
goto bad;
}
/*
* Source scope check: if a packet can't be delivered to its
* destination for the reason that the destination is beyond the scope